Short Hill Intervals
Short hill intervals are the most common type of hill training used by runners. They are a very time effective training method for developing muscular strength, power, running efficiency, stride length, cadence, anaerobic and aerobic endurance. Ultimately, including short hill intervals as part of a structured training plan will improve your running form, running speed and race performance.
A typical short hill interval training session would involve running repetitions of between 30 and 90 seconds duration, up a moderate (4-6% gradient) or sometimes a slightly steeper gradient (>7%). This is normally followed by an active recovery jog back down the hill, before repeating a set number of times.
One key point with short hills is the level of adaptability. The training focus, can be easily altered by adjusting the intensity and duration of the hill reps, by adjusting the length of the recovery, and the gradient of the hill. In this way short hill workouts can easily be tailored to meet the training requirements of sprinters, middle distance and long distance runners.
In fact, there are a number of different ways that we can use these key running workouts to improve our running performance. In this article we’ll look at the training benefits of short hills. Look at how they differ from hill sprints.
Then we’ll take a look at some example short hill sessions and the associated training benefits. I’ll also share some of my training data from these hill sessions to highlight the training benefits and the key differences between these.
The training benefit of short hills
Short hill intervals have a number of key training benefits. They can be used for the development of stride length and running cadence. To increase power, strength, muscular endurance and running efficiency. To improve anaerobic capacity and endurance as well as aerobic endurance. And most importantly to improve our running speed.
As such we can use short hills to target many different areas that contribute to endurance running performance. In fact these sessions are highly adaptable and there are a number of ways we can adjust short hill workouts that alter the training benefits.
5 Different ways we can adapt short hill intervals:
- Intensity of the hill repetition: with short hills this can vary from close to maximal sustainable effort to 5km race intensity. The key to remember here is that we’re talking about intensity rather than pace. We’re not trying to match the speed we run on flat terrain, but rather the intensity.
- Duration of hill: typically from 30 to ~ 90seconds. Shorter hills allow a higher work intensity, whereas longer hills bring in a greater endurance component. In most cases short hills would not be run for much longer than 60seconds.
- Length of the recovery period: this can range from a 1:1 to 1:8 work to recovery ratio. The recovery period is largely dictated by the intensity and duration of the hill interval. Higher intensity efforts require longer recovery periods. The gradient can also have an effect here – steeper gradients make it easier to reduce the recovery time between intervals.
- Intensity of recovery period: this can vary from a very easy jog/walk recovery, to a more steady pace such as marathon pace, or possibly slightly quicker. The recovery periods can be used to increase the average intensity of the workout. By doing this we can manipulate the workout to combine the benefits of hill training and threshold training. Or we can reduce the recovery intensity to allow a higher work rate during hill repetitions
- The hill gradient: most hills workouts are normally run on gradients of 3% up to 10%. The gradient can affect cadence, interval pace, ground contact time and power.
How Short hills differ from Hill Sprints
When most runners think of short hills they think of hill sprints. However, unlike hill sprints the intensity of short hills are not quite maximal. When we talk about ‘maximal’ intensity or speed, we’re referring to the highest intensity, or fastest speed, we can run. Since our true maximal running speed can only be sustained for very short periods – just a few seconds at a time – the average pace of short hills are slightly below maximal running intensity. Yes they’re fast. And yes they are intense. But they’re not quite maximal.
Whilst hill sprints are all about maximal effort. Short hills place a greater emphasis on the development of the key energy systems used when running middle and long-distance events (both the anaerobic ‘Lactate’ system and aerobic energy systems).
Here there is another difference between hill sprints and short hills. With hill sprints it’s all about pushing the upper (maximal) limits of stride length and cadence. Whereas with short hills the training benefit comes through an improved ability to sustain a ‘near’ maximal running cadence and stride length. Whilst our stride length is actually not longer during hill running (due to the vertical aspect of hill running), we actually generate more power per foot strike. As such hills are generally beneficial for the development of stride length.
With short hills, the intensity varies depending on the purpose of the session, the length of the hill, and recovery period. It may be anywhere from 400m intensity to 5k running intensity*.
Different types of Short hills
Clearly there’s a very big difference between running a hill interval at 400m and 5k race intensity. Between running hills on a moderate (3-6%) slope and a steep 10% gradient. And then we still need to factor in hill interval length, recovery length and intensity. Taken together we can see just how versatile short hill training sessions can be. All you need is a bit of an understanding as to the purpose of the session.
As short hills cover a relatively wide range of distances and intensities, the training purpose and benefit can vary greatly. In this way the intensity, length, gradient and the recovery period can all be manipulated to significantly alter the training effect.
Here it’s useful to consider the primary energy systems being used and the purpose of the hill session. In this way we can break short hills down into three main types:
- Short hill repetitions for training anaerobic capacity
- Short hill repetitions for training anaerobic endurance and conditioning
- Short hill repetitions for training aerobic and anaerobic endurance
Short hills for training anaerobic capacity
Often overlooked by distance runners, these short intense hills can be highly effective for improving running performance. Whilst the primary focus here is to develop anaerobic capacity, research has shown that these short intense hills can lead to significant improvements in ventilatory threshold and time to exhaustion.
One key benefit of these short anaerobic hills comes through improved neuromuscular coordination. And an improved ability to sustain a ‘near’ maximal running cadence and stride length. Whilst our stride length is actually not longer during hill running (due to the vertical aspect of hill running), we generate more power per stride. As such hills are beneficial for the development of stride length.
In order for these short hills to push the limits of our anaerobic capacity, they need to be relatively short (~20-40seconds) and run at a very high intensity. You should complete each repetition feeling like you couldn’t continue for much longer at that intensity.
As these are so intense, the recovery periods need to be extended. And the work to recovery ratio would typically be in the range of 1:4-1:8 – depending on interval length, intensity, and your fitness level.
What are the key training benefits from short anaerobic hills? Here the key training benefits are improved anaerobic capacity, power, strength, running speed, improved ability to sustain high running cadence and long stride length. Whilst the primary focus with these hills is to develop anaerobic capacity these can also benefit aerobic fitness.
Typical contribution of anaerobic and aerobic energy systems during anaerobic capacity hills:
Example Short hill workout for training anaerobic capacity
Example hill session 1: 5-8 x 30secs hills at near “30second” maximal intensity, with a 3-5minute very easy jog recovery between efforts.
The primary focus here is to develop anaerobic capacity. However, these are also great for strength, power, speed, stride length and cadence. A moderately steep gradient (~5-7%) works well with these short intense hills. This is just steep enough to increase force production without significantly reducing cadence. A key consideration with hills is that as gradient increases it becomes harder to maintain faster cadences.
An advantage with this length of hill is that lactate levels don’t build up significantly.
Whilst completing only 5-8 reps seems like a very small number for most endurance athletes. If you run these at the right intensity then there isn’t a need to run more than this.
Below you can see the summary data for my running cadence, ground contact time, running pace running power (measured with the Stryd footpod) during the anaerobic capacity hills. The data is the average for the hill intervals and the hills were run on a 6.5% gradient.
Summary of my training data for 5 x 30secs anaerobic capacity intervals:
Here, I’ve removed the first 5 seconds of data from each hill repetition as the lower power during the first 5 seconds significantly pulls down the average.
Using power rather than pace to analyse these sessions allows you to compare these hills with the equivalent flat ground running intensity.
Whereas running pace during the hills is approximately 5% slower than vVO2max pace. The actual power required to run at that pace was approximately 26% higher than VO2max power. This highlights why pace is not a good indicator of running intensity during hill running.
As mentioned both cadence and power have increased significantly compared with the equivalent at VO2max intensity – cadence is ~9% higher but crucially the increase in power is ~26% higher.
It’s the greater increase in the power compared with cadence that’s key here. The larger increase in power, compared with the slightly smaller increase in cadence, means that for every step of uphill running we’re generating more force per foot strike.
Clearly using these short anaerobic capacity hill repetitions is an effective way to push the upper limits of cadence and power.
So we’ve looked at an effective workout for increasing, running power, cadence and anaerobic capacity. What about training anaerobic endurance?
Short hills for training anaerobic endurance and conditioning
Whereas anaerobic capacity refers to our capacity to produce energy anaerobically. Anaerobic endurance refers to our ability to continue to produce energy anaerobically. This also requires an improved ability to tolerate and clear the build up of acidity as lactate levels rise.
In order to place an emphasis on anaerobic endurance we can extend the length of the intervals. An example would be to extend the length of the hill interval to around 60seconds, whilst slightly reducing the work to recovery ratio. This increases the overall contribution of energy from the anaerobic ‘lactate’ energy system, compared with the shorter anaerobic capacity hills.
Overall the intensity of these hills is slightly lower than the anaerobic capacity hills in session 1. However, the increased duration leads to a build up of lactate and associated hydrogen ions. As such these hills are beneficial for anaerobic conditioning as well as anaerobic endurance.
Another factor here is that despite a large anaerobic energy contribution. We would normally see a slightly greater aerobic energy contribution especially amongst endurance athletes.
Typical energy contribution during anaerobic endurance hills:
Session 2: 5-6 x 60seconds at just above, or around, 800m intensity (not pace), with 3-5mins very easy jog recovery between efforts.
When the hills are extended to around a minute it’s important to consider gradient. In this case a steeper gradient makes maintaining a faster cadence more difficult. So a more moderate gradient (4-5%) is generally more beneficial. This allows a good amount of power per foot strike whilst still maintaining a fast cadence.
Unlike, with session 1, lactate levels start to accumulate during this session. This makes this an effective hill workout for development of strength, speed endurance, stride length, cadence and anaerobic power and conditioning. However, you can see from my training data (below) that when we extending the length of these hills, cadence is reduced compared with the 30second hills. However, despite this cadence is still well above lactate threshold cadence.
Summary data from my 5 x 60s anaerobic endurance hill training sessions:
Again, I’ve removed the first 5 seconds of data from each hill repetition as the lower power during the first 5 seconds pulls down the average.
Again both cadence and power have increased compared with the equivalent at VO2max intensity. Cadence is ~3% higher but crucially the increase in power is ~15% higher.
As with session 1 we can see that the increase in power was greater than the increase in cadence. Showing that this hill session is effective for increasing the force per foot strike.
From the data we can see that Session 1 placed a greater emphasis on cadence. Session 2 brings in more of an endurance element for both anaerobic endurance, power per foot strike and the ability to maintain a fast cadence.
The data shows that these are both good for training running cadence – although the 5 x 30s was significantly better in this respect. At the same time running power is significantly increased above VO2max power. And importantly the power per foot strike is increased. So not only are these great for cadence development but also for improving stride length. And whilst the primary focus is anaerobic capacity and anaerobic endurance these are also highly beneficial for endurance athletes
Important note: running at these intensities is not recommended unless you’ve already built a solid base fitness first. You also need to build towards these by including preparatory hill sessions that are run at lower intensities. After building conditioning to run these hills start at lower intensities first and look to progressively increase the intensity as your body adapts (e.g. 3km intensity > 1500m intensity > 800m intensity). These sessions are generally used sparingly and need to be carefully integrated within a training plan.
Short hill repetitions for training aerobic and anaerobic endurance
So we’ve seen how we can target anaerobic capacity and anaerobic endurance. What about if we want to put more focus on aerobic endurance? The first thing we need to do here is reduce the intensity slightly. We should also reduce the recovery period. This allows us to train at an intensity where aerobic metabolism makes up a greater proportion of the total energy needs
So what intensity should we use for these hills to target aerobic and anaerobic endurance? In order to provide a strong training benefit for aerobic energy systems, whilst still working anaerobic metabolism, the intensity really needs to be around 1500/3000m intensity. At 1500m intensity anaerobic energy provides approximately 20% of total energy.
These top end aerobic hill sessions place less emphasis on power development compared with anaerobic capacity and anaerobic endurance hill sessions. However these still cause increased force production per foot strike and are therefore beneficial for strength development. In this sense these hills place a greater emphasis on muscular strength endurance rather than power. Especially when combined with shorter recoveries.
As they are run at close to VO2max intensity they help to improve our ability to absorb, transport and use oxygen. At the same time these sessions help to improve muscular strength, muscular endurance, fatigue resistance of slow and fast twitch muscle fibres. And whilst anaerobic metabolism isn’t the primary energy source, blood lactate levels still increase, so we improve our ability to tolerate and clear increased acidity. Another training benefit of these short aerobic hills is to improve our ability to maintain a high running cadence and a good stride length.
Typical energy contribution during combined aerobic/anaerobic endurance hills
Example short hill session for aerobic and anaerobic endurance include:
Session 3: 8-12* x 60secs hills at 1500/3000m intensity, with an easy jog recovery.
*This can be increased for more experienced runners.
Session 4: Tempo Intervals 2-3 sets of 8-10 x 150m short hills (5.5% gradient) at around 3km intensity, with recovery run at easy/steady intensity.
This aerobic endurance hill training session places a greater emphasis on aerobic endurance.
This session has the advantage of combing uphill intervals at near VO2max intensity, with a steady downhill recovery. This keeps the average intensity (uphill interval + downhill recovery) at very close to lactate threshold intensity. Making this session ideal for working the upper limits of aerobic capacity as well as the lactate threshold. At the same time this session is great for muscular and strength endurance and can lead to improvements in running cadence and stride length at intensities between VO2max and lactate threshold intensity.
Surprisingly this session also has a strong anaerobic component making it a very good around hill sessions.
You can read more about Tempo hills including training data here: >> Tempo hill intervals.
Short hill intervals summary
- Short hill intervals involve running short intervals of 30-90seconds duration, up a moderate or moderately-steep slope.
- The intensity of these intervals would typically be run at between 400m and 5000m intensity, depending on the training purpose and focus.
- Short hill workouts help to develop muscle strength, power and efficiency. But to a lesser extent than hill sprints.
- Short hills provide a strong training stimulus for developing running cadence and stride length. Whereas hill sprints develop maximal cadence and stride length, short hills are useful for developing our ability to sustain a fast cadence and long stride.
- Short hills can be used to improve both anaerobic and aerobic endurance.
- The extent to which energy system is developed mainly comes down to the intensity of the intervals, and length of recovery. As such, the contribution of anaerobic and aerobic energy systems can be altered by altering the intensity of hill interval.
- As well as adjusting interval intensity, we can reduce the length of recovery, or increase recovery intensity. This increases the average intensity of the session. A shorter recovery can be used to make the session more aerobic. A longer recovery period, allows a greater intensity during the hill interval.